“We’ve directly measured four separate types of atoms from interstellar space and the composition just doesn’t match up with what we see in the solar system,” said Mr. Christian. “IBEX’s observations shed a whole new light on the mysterious zone where the solar system ends and interstellar space begins.”

The agency reported its findings in a series of papers this week, noting the spacecraft has intercepted hydrogen, helium, neon and oxygen atoms.

A great magnetic bubble surrounds the solar system as it cruises through the galaxy. The sun pumps the inside of the bubble full of solar particles that stream out to the edge until they collide with the material that fills the rest of the galaxy, at a complex boundary called the heliosheath.

On the other side of the boundary, electrically charged particles from the galactic wind blow by, but rebound off the heliosheath, never to enter the solar system. Neutral particles, on the other hand, remain stuck across the boundary, continuing on another 7.5 billion miles for 30 years until they get caught by the sun’s gravity, when they are pulled back.

More than just helping to determine the distribution of elements in the galactic wind, these new measurements give clues about how and where our solar system formed, the forces that physically shape our solar system, and even the history of other stars in the Milky Way, said NASA officials.

“Our solar system is different than the space right outside it and that suggests two possibilities,” said David McComas the principal investigator for IBEX at the Southwest Research Institute in San Antonio, Texas. “Either the solar system evolved in a separate, more oxygen-rich part of the galaxy than where we currently reside or a great deal of critical, life-giving oxygen lies trapped in interstellar dust grains or ices, unable to move freely throughout space.” Either way, this affects scientific models of how our solar system – and life – formed.”

Studying the galactic wind also provides scientists with information about how our solar system interacts with the rest of space, which is congruent with an important IBEX goal. Classified as a NASA Explorer Mission, the spacecraft’s main objective is to study the heliosheath, that outer boundary of the solar system’s magnetic bubble — or heliosphere — where particles from the solar wind meet the galactic wind.